xref: /openbmc/linux/include/net/sctp/structs.h (revision 96de0e252cedffad61b3cb5e05662c591898e69a)
1 /* SCTP kernel reference Implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  *
7  * This file is part of the SCTP kernel reference Implementation
8  *
9  * The SCTP reference implementation is free software;
10  * you can redistribute it and/or modify it under the terms of
11  * the GNU General Public License as published by
12  * the Free Software Foundation; either version 2, or (at your option)
13  * any later version.
14  *
15  * The SCTP reference implementation is distributed in the hope that it
16  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
17  *		   ************************
18  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
19  * See the GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with GNU CC; see the file COPYING.  If not, write to
23  * the Free Software Foundation, 59 Temple Place - Suite 330,
24  * Boston, MA 02111-1307, USA.
25  *
26  * Please send any bug reports or fixes you make to the
27  * email addresses:
28  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
29  *
30  * Or submit a bug report through the following website:
31  *    http://www.sf.net/projects/lksctp
32  *
33  * Written or modified by:
34  *    Randall Stewart	    <randall@sctp.chicago.il.us>
35  *    Ken Morneau	    <kmorneau@cisco.com>
36  *    Qiaobing Xie	    <qxie1@email.mot.com>
37  *    La Monte H.P. Yarroll <piggy@acm.org>
38  *    Karl Knutson	    <karl@athena.chicago.il.us>
39  *    Jon Grimm		    <jgrimm@us.ibm.com>
40  *    Xingang Guo	    <xingang.guo@intel.com>
41  *    Hui Huang		    <hui.huang@nokia.com>
42  *    Sridhar Samudrala	    <sri@us.ibm.com>
43  *    Daisy Chang	    <daisyc@us.ibm.com>
44  *    Dajiang Zhang	    <dajiang.zhang@nokia.com>
45  *    Ardelle Fan	    <ardelle.fan@intel.com>
46  *    Ryan Layer	    <rmlayer@us.ibm.com>
47  *    Anup Pemmaiah	    <pemmaiah@cc.usu.edu>
48  *    Kevin Gao             <kevin.gao@intel.com>
49  *
50  * Any bugs reported given to us we will try to fix... any fixes shared will
51  * be incorporated into the next SCTP release.
52  */
53 
54 #ifndef __sctp_structs_h__
55 #define __sctp_structs_h__
56 
57 #include <linux/time.h>		/* We get struct timespec.    */
58 #include <linux/socket.h>	/* linux/in.h needs this!!    */
59 #include <linux/in.h>		/* We get struct sockaddr_in. */
60 #include <linux/in6.h>		/* We get struct in6_addr     */
61 #include <linux/ipv6.h>
62 #include <asm/param.h>		/* We get MAXHOSTNAMELEN.     */
63 #include <asm/atomic.h>		/* This gets us atomic counters.  */
64 #include <linux/skbuff.h>	/* We need sk_buff_head. */
65 #include <linux/workqueue.h>	/* We need tq_struct.	 */
66 #include <linux/sctp.h>		/* We need sctp* header structs.  */
67 #include <net/sctp/auth.h>	/* We need auth specific structs */
68 
69 /* A convenience structure for handling sockaddr structures.
70  * We should wean ourselves off this.
71  */
72 union sctp_addr {
73 	struct sockaddr_in v4;
74 	struct sockaddr_in6 v6;
75 	struct sockaddr sa;
76 };
77 
78 /* Forward declarations for data structures. */
79 struct sctp_globals;
80 struct sctp_endpoint;
81 struct sctp_association;
82 struct sctp_transport;
83 struct sctp_packet;
84 struct sctp_chunk;
85 struct sctp_inq;
86 struct sctp_outq;
87 struct sctp_bind_addr;
88 struct sctp_ulpq;
89 struct sctp_ep_common;
90 struct sctp_ssnmap;
91 struct crypto_hash;
92 
93 
94 #include <net/sctp/tsnmap.h>
95 #include <net/sctp/ulpevent.h>
96 #include <net/sctp/ulpqueue.h>
97 
98 /* Structures useful for managing bind/connect. */
99 
100 struct sctp_bind_bucket {
101 	unsigned short	port;
102 	unsigned short	fastreuse;
103 	struct sctp_bind_bucket *next;
104 	struct sctp_bind_bucket **pprev;
105 	struct hlist_head	owner;
106 };
107 
108 struct sctp_bind_hashbucket {
109 	spinlock_t	lock;
110 	struct sctp_bind_bucket	*chain;
111 };
112 
113 /* Used for hashing all associations.  */
114 struct sctp_hashbucket {
115 	rwlock_t	lock;
116 	struct sctp_ep_common  *chain;
117 } __attribute__((__aligned__(8)));
118 
119 
120 /* The SCTP globals structure. */
121 extern struct sctp_globals {
122 	/* RFC2960 Section 14. Suggested SCTP Protocol Parameter Values
123 	 *
124 	 * The following protocol parameters are RECOMMENDED:
125 	 *
126 	 * RTO.Initial		    - 3	 seconds
127 	 * RTO.Min		    - 1	 second
128 	 * RTO.Max		   -  60 seconds
129 	 * RTO.Alpha		    - 1/8  (3 when converted to right shifts.)
130 	 * RTO.Beta		    - 1/4  (2 when converted to right shifts.)
131 	 */
132 	unsigned int rto_initial;
133 	unsigned int rto_min;
134 	unsigned int rto_max;
135 
136 	/* Note: rto_alpha and rto_beta are really defined as inverse
137 	 * powers of two to facilitate integer operations.
138 	 */
139 	int rto_alpha;
140 	int rto_beta;
141 
142 	/* Max.Burst		    - 4 */
143 	int max_burst;
144 
145 	/* Whether Cookie Preservative is enabled(1) or not(0) */
146 	int cookie_preserve_enable;
147 
148 	/* Valid.Cookie.Life	    - 60  seconds  */
149 	unsigned int valid_cookie_life;
150 
151 	/* Delayed SACK timeout  200ms default*/
152 	unsigned int sack_timeout;
153 
154 	/* HB.interval		    - 30 seconds  */
155 	unsigned int hb_interval;
156 
157 	/* Association.Max.Retrans  - 10 attempts
158 	 * Path.Max.Retrans	    - 5	 attempts (per destination address)
159 	 * Max.Init.Retransmits	    - 8	 attempts
160 	 */
161 	int max_retrans_association;
162 	int max_retrans_path;
163 	int max_retrans_init;
164 
165 	/*
166 	 * Policy for preforming sctp/socket accounting
167 	 * 0   - do socket level accounting, all assocs share sk_sndbuf
168 	 * 1   - do sctp accounting, each asoc may use sk_sndbuf bytes
169 	 */
170 	int sndbuf_policy;
171 
172 	/*
173 	 * Policy for preforming sctp/socket accounting
174 	 * 0   - do socket level accounting, all assocs share sk_rcvbuf
175 	 * 1   - do sctp accounting, each asoc may use sk_rcvbuf bytes
176 	 */
177 	int rcvbuf_policy;
178 
179 	/* The following variables are implementation specific.	 */
180 
181 	/* Default initialization values to be applied to new associations. */
182 	__u16 max_instreams;
183 	__u16 max_outstreams;
184 
185 	/* This is a list of groups of functions for each address
186 	 * family that we support.
187 	 */
188 	struct list_head address_families;
189 
190 	/* This is the hash of all endpoints. */
191 	int ep_hashsize;
192 	struct sctp_hashbucket *ep_hashtable;
193 
194 	/* This is the hash of all associations. */
195 	int assoc_hashsize;
196 	struct sctp_hashbucket *assoc_hashtable;
197 
198 	/* This is the sctp port control hash.	*/
199 	int port_hashsize;
200 	struct sctp_bind_hashbucket *port_hashtable;
201 
202 	/* This is the global local address list.
203 	 * We actively maintain this complete list of addresses on
204 	 * the system by catching address add/delete events.
205 	 *
206 	 * It is a list of sctp_sockaddr_entry.
207 	 */
208 	struct list_head local_addr_list;
209 
210 	/* Lock that protects the local_addr_list writers */
211 	spinlock_t addr_list_lock;
212 
213 	/* Flag to indicate if addip is enabled. */
214 	int addip_enable;
215 
216 	/* Flag to indicate if PR-SCTP is enabled. */
217 	int prsctp_enable;
218 
219 	/* Flag to idicate if SCTP-AUTH is enabled */
220 	int auth_enable;
221 } sctp_globals;
222 
223 #define sctp_rto_initial		(sctp_globals.rto_initial)
224 #define sctp_rto_min			(sctp_globals.rto_min)
225 #define sctp_rto_max			(sctp_globals.rto_max)
226 #define sctp_rto_alpha			(sctp_globals.rto_alpha)
227 #define sctp_rto_beta			(sctp_globals.rto_beta)
228 #define sctp_max_burst			(sctp_globals.max_burst)
229 #define sctp_valid_cookie_life		(sctp_globals.valid_cookie_life)
230 #define sctp_cookie_preserve_enable	(sctp_globals.cookie_preserve_enable)
231 #define sctp_max_retrans_association	(sctp_globals.max_retrans_association)
232 #define sctp_sndbuf_policy	 	(sctp_globals.sndbuf_policy)
233 #define sctp_rcvbuf_policy	 	(sctp_globals.rcvbuf_policy)
234 #define sctp_max_retrans_path		(sctp_globals.max_retrans_path)
235 #define sctp_max_retrans_init		(sctp_globals.max_retrans_init)
236 #define sctp_sack_timeout		(sctp_globals.sack_timeout)
237 #define sctp_hb_interval		(sctp_globals.hb_interval)
238 #define sctp_max_instreams		(sctp_globals.max_instreams)
239 #define sctp_max_outstreams		(sctp_globals.max_outstreams)
240 #define sctp_address_families		(sctp_globals.address_families)
241 #define sctp_ep_hashsize		(sctp_globals.ep_hashsize)
242 #define sctp_ep_hashtable		(sctp_globals.ep_hashtable)
243 #define sctp_assoc_hashsize		(sctp_globals.assoc_hashsize)
244 #define sctp_assoc_hashtable		(sctp_globals.assoc_hashtable)
245 #define sctp_port_hashsize		(sctp_globals.port_hashsize)
246 #define sctp_port_rover			(sctp_globals.port_rover)
247 #define sctp_port_alloc_lock		(sctp_globals.port_alloc_lock)
248 #define sctp_port_hashtable		(sctp_globals.port_hashtable)
249 #define sctp_local_addr_list		(sctp_globals.local_addr_list)
250 #define sctp_local_addr_lock		(sctp_globals.addr_list_lock)
251 #define sctp_addip_enable		(sctp_globals.addip_enable)
252 #define sctp_prsctp_enable		(sctp_globals.prsctp_enable)
253 #define sctp_auth_enable		(sctp_globals.auth_enable)
254 
255 /* SCTP Socket type: UDP or TCP style. */
256 typedef enum {
257 	SCTP_SOCKET_UDP = 0,
258 	SCTP_SOCKET_UDP_HIGH_BANDWIDTH,
259 	SCTP_SOCKET_TCP
260 } sctp_socket_type_t;
261 
262 /* Per socket SCTP information. */
263 struct sctp_sock {
264 	/* inet_sock has to be the first member of sctp_sock */
265 	struct inet_sock inet;
266 	/* What kind of a socket is this? */
267 	sctp_socket_type_t type;
268 
269 	/* PF_ family specific functions.  */
270 	struct sctp_pf *pf;
271 
272 	/* Access to HMAC transform. */
273 	struct crypto_hash *hmac;
274 
275 	/* What is our base endpointer? */
276 	struct sctp_endpoint *ep;
277 
278 	struct sctp_bind_bucket *bind_hash;
279 	/* Various Socket Options.  */
280 	__u16 default_stream;
281 	__u32 default_ppid;
282 	__u16 default_flags;
283 	__u32 default_context;
284 	__u32 default_timetolive;
285 	__u32 default_rcv_context;
286 	int max_burst;
287 
288 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
289 	 * the destination address every heartbeat interval. This value
290 	 * will be inherited by all new associations.
291 	 */
292 	__u32 hbinterval;
293 
294 	/* This is the max_retrans value for new associations. */
295 	__u16 pathmaxrxt;
296 
297 	/* The initial Path MTU to use for new associations. */
298 	__u32 pathmtu;
299 
300 	/* The default SACK delay timeout for new associations. */
301 	__u32 sackdelay;
302 
303 	/* Flags controling Heartbeat, SACK delay, and Path MTU Discovery. */
304 	__u32 param_flags;
305 
306 	struct sctp_initmsg initmsg;
307 	struct sctp_rtoinfo rtoinfo;
308 	struct sctp_paddrparams paddrparam;
309 	struct sctp_event_subscribe subscribe;
310 	struct sctp_assocparams assocparams;
311 	int user_frag;
312 	__u32 autoclose;
313 	__u8 nodelay;
314 	__u8 disable_fragments;
315 	__u8 v4mapped;
316 	__u8 frag_interleave;
317 	__u32 adaptation_ind;
318 	__u32 pd_point;
319 
320 	atomic_t pd_mode;
321 	/* Receive to here while partial delivery is in effect. */
322 	struct sk_buff_head pd_lobby;
323 };
324 
325 static inline struct sctp_sock *sctp_sk(const struct sock *sk)
326 {
327        return (struct sctp_sock *)sk;
328 }
329 
330 static inline struct sock *sctp_opt2sk(const struct sctp_sock *sp)
331 {
332        return (struct sock *)sp;
333 }
334 
335 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
336 struct sctp6_sock {
337        struct sctp_sock  sctp;
338        struct ipv6_pinfo inet6;
339 };
340 #endif /* CONFIG_IPV6 */
341 
342 
343 /* This is our APPLICATION-SPECIFIC state cookie.
344  * THIS IS NOT DICTATED BY THE SPECIFICATION.
345  */
346 /* These are the parts of an association which we send in the cookie.
347  * Most of these are straight out of:
348  * RFC2960 12.2 Parameters necessary per association (i.e. the TCB)
349  *
350  */
351 
352 struct sctp_cookie {
353 
354 	/* My	       : Tag expected in every inbound packet and sent
355 	 * Verification: in the INIT or INIT ACK chunk.
356 	 * Tag	       :
357 	 */
358 	__u32 my_vtag;
359 
360 	/* Peer's      : Tag expected in every outbound packet except
361 	 * Verification: in the INIT chunk.
362 	 * Tag	       :
363 	 */
364 	__u32 peer_vtag;
365 
366 	/* The rest of these are not from the spec, but really need to
367 	 * be in the cookie.
368 	 */
369 
370 	/* My Tie Tag  : Assist in discovering a restarting association. */
371 	__u32 my_ttag;
372 
373 	/* Peer's Tie Tag: Assist in discovering a restarting association. */
374 	__u32 peer_ttag;
375 
376 	/* When does this cookie expire? */
377 	struct timeval expiration;
378 
379 	/* Number of inbound/outbound streams which are set
380 	 * and negotiated during the INIT process.
381 	 */
382 	__u16 sinit_num_ostreams;
383 	__u16 sinit_max_instreams;
384 
385 	/* This is the first sequence number I used.  */
386 	__u32 initial_tsn;
387 
388 	/* This holds the originating address of the INIT packet.  */
389 	union sctp_addr peer_addr;
390 
391 	/* IG Section 2.35.3
392 	 * Include the source port of the INIT-ACK
393 	 */
394 	__u16		my_port;
395 
396 	__u8 prsctp_capable;
397 
398 	/* Padding for future use */
399 	__u8 padding;
400 
401 	__u32 adaptation_ind;
402 
403 	__u8 auth_random[sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH];
404 	__u8 auth_hmacs[SCTP_AUTH_NUM_HMACS + 2];
405 	__u8 auth_chunks[sizeof(sctp_paramhdr_t) + SCTP_AUTH_MAX_CHUNKS];
406 
407 	/* This is a shim for my peer's INIT packet, followed by
408 	 * a copy of the raw address list of the association.
409 	 * The length of the raw address list is saved in the
410 	 * raw_addr_list_len field, which will be used at the time when
411 	 * the association TCB is re-constructed from the cookie.
412 	 */
413 	__u32 raw_addr_list_len;
414 	struct sctp_init_chunk peer_init[0];
415 };
416 
417 
418 /* The format of our cookie that we send to our peer. */
419 struct sctp_signed_cookie {
420 	__u8 signature[SCTP_SECRET_SIZE];
421 	__u32 __pad;		/* force sctp_cookie alignment to 64 bits */
422 	struct sctp_cookie c;
423 } __attribute__((packed));
424 
425 /* This is another convenience type to allocate memory for address
426  * params for the maximum size and pass such structures around
427  * internally.
428  */
429 union sctp_addr_param {
430 	struct sctp_paramhdr p;
431 	struct sctp_ipv4addr_param v4;
432 	struct sctp_ipv6addr_param v6;
433 };
434 
435 /* A convenience type to allow walking through the various
436  * parameters and avoid casting all over the place.
437  */
438 union sctp_params {
439 	void *v;
440 	struct sctp_paramhdr *p;
441 	struct sctp_cookie_preserve_param *life;
442 	struct sctp_hostname_param *dns;
443 	struct sctp_cookie_param *cookie;
444 	struct sctp_supported_addrs_param *sat;
445 	struct sctp_ipv4addr_param *v4;
446 	struct sctp_ipv6addr_param *v6;
447 	union sctp_addr_param *addr;
448 	struct sctp_adaptation_ind_param *aind;
449 	struct sctp_supported_ext_param *ext;
450 	struct sctp_random_param *random;
451 	struct sctp_chunks_param *chunks;
452 	struct sctp_hmac_algo_param *hmac_algo;
453 };
454 
455 /* RFC 2960.  Section 3.3.5 Heartbeat.
456  *    Heartbeat Information: variable length
457  *    The Sender-specific Heartbeat Info field should normally include
458  *    information about the sender's current time when this HEARTBEAT
459  *    chunk is sent and the destination transport address to which this
460  *    HEARTBEAT is sent (see Section 8.3).
461  */
462 typedef struct sctp_sender_hb_info {
463 	struct sctp_paramhdr param_hdr;
464 	union sctp_addr daddr;
465 	unsigned long sent_at;
466 	__u64 hb_nonce;
467 } __attribute__((packed)) sctp_sender_hb_info_t;
468 
469 /*
470  *  RFC 2960 1.3.2 Sequenced Delivery within Streams
471  *
472  *  The term "stream" is used in SCTP to refer to a sequence of user
473  *  messages that are to be delivered to the upper-layer protocol in
474  *  order with respect to other messages within the same stream.  This is
475  *  in contrast to its usage in TCP, where it refers to a sequence of
476  *  bytes (in this document a byte is assumed to be eight bits).
477  *  ...
478  *
479  *  This is the structure we use to track both our outbound and inbound
480  *  SSN, or Stream Sequence Numbers.
481  */
482 
483 struct sctp_stream {
484 	__u16 *ssn;
485 	unsigned int len;
486 };
487 
488 struct sctp_ssnmap {
489 	struct sctp_stream in;
490 	struct sctp_stream out;
491 	int malloced;
492 };
493 
494 struct sctp_ssnmap *sctp_ssnmap_new(__u16 in, __u16 out,
495 				    gfp_t gfp);
496 void sctp_ssnmap_free(struct sctp_ssnmap *map);
497 void sctp_ssnmap_clear(struct sctp_ssnmap *map);
498 
499 /* What is the current SSN number for this stream? */
500 static inline __u16 sctp_ssn_peek(struct sctp_stream *stream, __u16 id)
501 {
502 	return stream->ssn[id];
503 }
504 
505 /* Return the next SSN number for this stream.	*/
506 static inline __u16 sctp_ssn_next(struct sctp_stream *stream, __u16 id)
507 {
508 	return stream->ssn[id]++;
509 }
510 
511 /* Skip over this ssn and all below. */
512 static inline void sctp_ssn_skip(struct sctp_stream *stream, __u16 id,
513 				 __u16 ssn)
514 {
515 	stream->ssn[id] = ssn+1;
516 }
517 
518 /*
519  * Pointers to address related SCTP functions.
520  * (i.e. things that depend on the address family.)
521  */
522 struct sctp_af {
523 	int		(*sctp_xmit)	(struct sk_buff *skb,
524 					 struct sctp_transport *,
525 					 int ipfragok);
526 	int		(*setsockopt)	(struct sock *sk,
527 					 int level,
528 					 int optname,
529 					 char __user *optval,
530 					 int optlen);
531 	int		(*getsockopt)	(struct sock *sk,
532 					 int level,
533 					 int optname,
534 					 char __user *optval,
535 					 int __user *optlen);
536 	int		(*compat_setsockopt)	(struct sock *sk,
537 					 int level,
538 					 int optname,
539 					 char __user *optval,
540 					 int optlen);
541 	int		(*compat_getsockopt)	(struct sock *sk,
542 					 int level,
543 					 int optname,
544 					 char __user *optval,
545 					 int __user *optlen);
546 	struct dst_entry *(*get_dst)	(struct sctp_association *asoc,
547 					 union sctp_addr *daddr,
548 					 union sctp_addr *saddr);
549 	void		(*get_saddr)	(struct sctp_association *asoc,
550 					 struct dst_entry *dst,
551 					 union sctp_addr *daddr,
552 					 union sctp_addr *saddr);
553 	void		(*copy_addrlist) (struct list_head *,
554 					  struct net_device *);
555 	void		(*dst_saddr)	(union sctp_addr *saddr,
556 					 struct dst_entry *dst,
557 					 __be16 port);
558 	int		(*cmp_addr)	(const union sctp_addr *addr1,
559 					 const union sctp_addr *addr2);
560 	void		(*addr_copy)	(union sctp_addr *dst,
561 					 union sctp_addr *src);
562 	void		(*from_skb)	(union sctp_addr *,
563 					 struct sk_buff *skb,
564 					 int saddr);
565 	void		(*from_sk)	(union sctp_addr *,
566 					 struct sock *sk);
567 	void		(*to_sk_saddr)	(union sctp_addr *,
568 					 struct sock *sk);
569 	void		(*to_sk_daddr)	(union sctp_addr *,
570 					 struct sock *sk);
571 	void		(*from_addr_param) (union sctp_addr *,
572 					    union sctp_addr_param *,
573 					    __be16 port, int iif);
574 	int		(*to_addr_param) (const union sctp_addr *,
575 					  union sctp_addr_param *);
576 	int		(*addr_valid)	(union sctp_addr *,
577 					 struct sctp_sock *,
578 					 const struct sk_buff *);
579 	sctp_scope_t	(*scope) (union sctp_addr *);
580 	void		(*inaddr_any)	(union sctp_addr *, __be16);
581 	int		(*is_any)	(const union sctp_addr *);
582 	int		(*available)	(union sctp_addr *,
583 					 struct sctp_sock *);
584 	int		(*skb_iif)	(const struct sk_buff *sk);
585 	int		(*is_ce)	(const struct sk_buff *sk);
586 	void		(*seq_dump_addr)(struct seq_file *seq,
587 					 union sctp_addr *addr);
588 	__u16		net_header_len;
589 	int		sockaddr_len;
590 	sa_family_t	sa_family;
591 	struct list_head list;
592 };
593 
594 struct sctp_af *sctp_get_af_specific(sa_family_t);
595 int sctp_register_af(struct sctp_af *);
596 
597 /* Protocol family functions. */
598 struct sctp_pf {
599 	void (*event_msgname)(struct sctp_ulpevent *, char *, int *);
600 	void (*skb_msgname)  (struct sk_buff *, char *, int *);
601 	int  (*af_supported) (sa_family_t, struct sctp_sock *);
602 	int  (*cmp_addr) (const union sctp_addr *,
603 			  const union sctp_addr *,
604 			  struct sctp_sock *);
605 	int  (*bind_verify) (struct sctp_sock *, union sctp_addr *);
606 	int  (*send_verify) (struct sctp_sock *, union sctp_addr *);
607 	int  (*supported_addrs)(const struct sctp_sock *, __be16 *);
608 	struct sock *(*create_accept_sk) (struct sock *sk,
609 					  struct sctp_association *asoc);
610 	void (*addr_v4map) (struct sctp_sock *, union sctp_addr *);
611 	struct sctp_af *af;
612 };
613 
614 
615 /* Structure to track chunk fragments that have been acked, but peer
616  * fragments of the same message have not.
617  */
618 struct sctp_datamsg {
619 	/* Chunks waiting to be submitted to lower layer. */
620 	struct list_head chunks;
621 	/* Chunks that have been transmitted. */
622 	struct list_head track;
623 	/* Reference counting. */
624 	atomic_t refcnt;
625 	/* When is this message no longer interesting to the peer? */
626 	unsigned long expires_at;
627 	/* Did the messenge fail to send? */
628 	int send_error;
629 	char send_failed;
630 	/* Control whether chunks from this message can be abandoned. */
631 	char can_abandon;
632 };
633 
634 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *,
635 					    struct sctp_sndrcvinfo *,
636 					    struct msghdr *, int len);
637 void sctp_datamsg_put(struct sctp_datamsg *);
638 void sctp_datamsg_free(struct sctp_datamsg *);
639 void sctp_datamsg_track(struct sctp_chunk *);
640 void sctp_chunk_fail(struct sctp_chunk *, int error);
641 int sctp_chunk_abandoned(struct sctp_chunk *);
642 
643 /* RFC2960 1.4 Key Terms
644  *
645  * o Chunk: A unit of information within an SCTP packet, consisting of
646  * a chunk header and chunk-specific content.
647  *
648  * As a matter of convenience, we remember the SCTP common header for
649  * each chunk as well as a few other header pointers...
650  */
651 struct sctp_chunk {
652 	struct list_head list;
653 
654 	atomic_t refcnt;
655 
656 	/* This is our link to the per-transport transmitted list.  */
657 	struct list_head transmitted_list;
658 
659 	/* This field is used by chunks that hold fragmented data.
660 	 * For the first fragment this is the list that holds the rest of
661 	 * fragments. For the remaining fragments, this is the link to the
662 	 * frag_list maintained in the first fragment.
663 	 */
664 	struct list_head frag_list;
665 
666 	/* This points to the sk_buff containing the actual data.  */
667 	struct sk_buff *skb;
668 
669 	/* These are the SCTP headers by reverse order in a packet.
670 	 * Note that some of these may happen more than once.  In that
671 	 * case, we point at the "current" one, whatever that means
672 	 * for that level of header.
673 	 */
674 
675 	/* We point this at the FIRST TLV parameter to chunk_hdr.  */
676 	union sctp_params param_hdr;
677 	union {
678 		__u8 *v;
679 		struct sctp_datahdr *data_hdr;
680 		struct sctp_inithdr *init_hdr;
681 		struct sctp_sackhdr *sack_hdr;
682 		struct sctp_heartbeathdr *hb_hdr;
683 		struct sctp_sender_hb_info *hbs_hdr;
684 		struct sctp_shutdownhdr *shutdown_hdr;
685 		struct sctp_signed_cookie *cookie_hdr;
686 		struct sctp_ecnehdr *ecne_hdr;
687 		struct sctp_cwrhdr *ecn_cwr_hdr;
688 		struct sctp_errhdr *err_hdr;
689 		struct sctp_addiphdr *addip_hdr;
690 		struct sctp_fwdtsn_hdr *fwdtsn_hdr;
691 		struct sctp_authhdr *auth_hdr;
692 	} subh;
693 
694 	__u8 *chunk_end;
695 
696 	struct sctp_chunkhdr *chunk_hdr;
697 	struct sctphdr *sctp_hdr;
698 
699 	/* This needs to be recoverable for SCTP_SEND_FAILED events. */
700 	struct sctp_sndrcvinfo sinfo;
701 
702 	/* Which association does this belong to?  */
703 	struct sctp_association *asoc;
704 
705 	/* What endpoint received this chunk? */
706 	struct sctp_ep_common *rcvr;
707 
708 	/* We fill this in if we are calculating RTT. */
709 	unsigned long sent_at;
710 
711 	/* What is the origin IP address for this chunk?  */
712 	union sctp_addr source;
713 	/* Destination address for this chunk. */
714 	union sctp_addr dest;
715 
716 	/* For outbound message, track all fragments for SEND_FAILED. */
717 	struct sctp_datamsg *msg;
718 
719 	/* For an inbound chunk, this tells us where it came from.
720 	 * For an outbound chunk, it tells us where we'd like it to
721 	 * go.	It is NULL if we have no preference.
722 	 */
723 	struct sctp_transport *transport;
724 
725 	/* SCTP-AUTH:  For the special case inbound processing of COOKIE-ECHO
726 	 * we need save a pointer to the AUTH chunk, since the SCTP-AUTH
727 	 * spec violates the principle premis that all chunks are processed
728 	 * in order.
729 	 */
730 	struct sk_buff *auth_chunk;
731 
732 	__u8 rtt_in_progress;	/* Is this chunk used for RTT calculation? */
733 	__u8 resent;		/* Has this chunk ever been retransmitted. */
734 	__u8 has_tsn;		/* Does this chunk have a TSN yet? */
735 	__u8 has_ssn;		/* Does this chunk have a SSN yet? */
736 	__u8 singleton;		/* Was this the only chunk in the packet? */
737 	__u8 end_of_packet;	/* Was this the last chunk in the packet? */
738 	__u8 ecn_ce_done;	/* Have we processed the ECN CE bit? */
739 	__u8 pdiscard;		/* Discard the whole packet now? */
740 	__u8 tsn_gap_acked;	/* Is this chunk acked by a GAP ACK? */
741 	__s8 fast_retransmit;	 /* Is this chunk fast retransmitted? */
742 	__u8 tsn_missing_report; /* Data chunk missing counter. */
743 	__u8 data_accepted; 	/* At least 1 chunk in this packet accepted */
744 	__u8 auth;		/* IN: was auth'ed | OUT: needs auth */
745 };
746 
747 void sctp_chunk_hold(struct sctp_chunk *);
748 void sctp_chunk_put(struct sctp_chunk *);
749 int sctp_user_addto_chunk(struct sctp_chunk *chunk, int off, int len,
750 			  struct iovec *data);
751 void sctp_chunk_free(struct sctp_chunk *);
752 void  *sctp_addto_chunk(struct sctp_chunk *, int len, const void *data);
753 struct sctp_chunk *sctp_chunkify(struct sk_buff *,
754 				 const struct sctp_association *,
755 				 struct sock *);
756 void sctp_init_addrs(struct sctp_chunk *, union sctp_addr *,
757 		     union sctp_addr *);
758 const union sctp_addr *sctp_source(const struct sctp_chunk *chunk);
759 
760 /* This is a structure for holding either an IPv6 or an IPv4 address.  */
761 struct sctp_sockaddr_entry {
762 	struct list_head list;
763 	struct rcu_head	rcu;
764 	union sctp_addr a;
765 	__u8 use_as_src;
766 	__u8 valid;
767 };
768 
769 typedef struct sctp_chunk *(sctp_packet_phandler_t)(struct sctp_association *);
770 
771 /* This structure holds lists of chunks as we are assembling for
772  * transmission.
773  */
774 struct sctp_packet {
775 	/* These are the SCTP header values (host order) for the packet. */
776 	__u16 source_port;
777 	__u16 destination_port;
778 	__u32 vtag;
779 
780 	/* This contains the payload chunks.  */
781 	struct list_head chunk_list;
782 
783 	/* This is the overhead of the sctp and ip headers. */
784 	size_t overhead;
785 	/* This is the total size of all chunks INCLUDING padding.  */
786 	size_t size;
787 
788 	/* The packet is destined for this transport address.
789 	 * The function we finally use to pass down to the next lower
790 	 * layer lives in the transport structure.
791 	 */
792 	struct sctp_transport *transport;
793 
794 	/* pointer to the auth chunk for this packet */
795 	struct sctp_chunk *auth;
796 
797 	/* This packet contains a COOKIE-ECHO chunk. */
798 	__u8 has_cookie_echo;
799 
800 	/* This packet contains a SACK chunk. */
801 	__u8 has_sack;
802 
803 	/* This packet contains an AUTH chunk */
804 	__u8 has_auth;
805 
806 	/* This packet contains at least 1 DATA chunk */
807 	__u8 has_data;
808 
809 	/* SCTP cannot fragment this packet. So let ip fragment it. */
810 	__u8 ipfragok;
811 
812 	__u8 malloced;
813 };
814 
815 struct sctp_packet *sctp_packet_init(struct sctp_packet *,
816 				     struct sctp_transport *,
817 				     __u16 sport, __u16 dport);
818 struct sctp_packet *sctp_packet_config(struct sctp_packet *, __u32 vtag, int);
819 sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *,
820                                        struct sctp_chunk *);
821 sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *,
822                                      struct sctp_chunk *);
823 int sctp_packet_transmit(struct sctp_packet *);
824 void sctp_packet_free(struct sctp_packet *);
825 
826 static inline int sctp_packet_empty(struct sctp_packet *packet)
827 {
828 	return (packet->size == packet->overhead);
829 }
830 
831 /* This represents a remote transport address.
832  * For local transport addresses, we just use union sctp_addr.
833  *
834  * RFC2960 Section 1.4 Key Terms
835  *
836  *   o	Transport address:  A Transport Address is traditionally defined
837  *	by Network Layer address, Transport Layer protocol and Transport
838  *	Layer port number.  In the case of SCTP running over IP, a
839  *	transport address is defined by the combination of an IP address
840  *	and an SCTP port number (where SCTP is the Transport protocol).
841  *
842  * RFC2960 Section 7.1 SCTP Differences from TCP Congestion control
843  *
844  *   o	The sender keeps a separate congestion control parameter set for
845  *	each of the destination addresses it can send to (not each
846  *	source-destination pair but for each destination).  The parameters
847  *	should decay if the address is not used for a long enough time
848  *	period.
849  *
850  */
851 struct sctp_transport {
852 	/* A list of transports. */
853 	struct list_head transports;
854 
855 	/* Reference counting. */
856 	atomic_t refcnt;
857 	int	 dead;
858 
859 	/* This is the peer's IP address and port. */
860 	union sctp_addr ipaddr;
861 
862 	/* These are the functions we call to handle LLP stuff.	 */
863 	struct sctp_af *af_specific;
864 
865 	/* Which association do we belong to?  */
866 	struct sctp_association *asoc;
867 
868 	/* RFC2960
869 	 *
870 	 * 12.3 Per Transport Address Data
871 	 *
872 	 * For each destination transport address in the peer's
873 	 * address list derived from the INIT or INIT ACK chunk, a
874 	 * number of data elements needs to be maintained including:
875 	 */
876 	__u32 rtt;		/* This is the most recent RTT.	 */
877 
878 	/* RTO	       : The current retransmission timeout value.  */
879 	unsigned long rto;
880 
881 	/* RTTVAR      : The current RTT variation.  */
882 	__u32 rttvar;
883 
884 	/* SRTT	       : The current smoothed round trip time.	*/
885 	__u32 srtt;
886 
887 	/* RTO-Pending : A flag used to track if one of the DATA
888 	 *		chunks sent to this address is currently being
889 	 *		used to compute a RTT. If this flag is 0,
890 	 *		the next DATA chunk sent to this destination
891 	 *		should be used to compute a RTT and this flag
892 	 *		should be set. Every time the RTT
893 	 *		calculation completes (i.e. the DATA chunk
894 	 *		is SACK'd) clear this flag.
895 	 */
896 	int rto_pending;
897 
898 	/*
899 	 * These are the congestion stats.
900 	 */
901 	/* cwnd	       : The current congestion window.	 */
902 	__u32 cwnd;		  /* This is the actual cwnd.  */
903 
904 	/* ssthresh    : The current slow start threshold value.  */
905 	__u32 ssthresh;
906 
907 	/* partial     : The tracking method for increase of cwnd when in
908 	 * bytes acked : congestion avoidance mode (see Section 6.2.2)
909 	 */
910 	__u32 partial_bytes_acked;
911 
912 	/* Data that has been sent, but not acknowledged. */
913 	__u32 flight_size;
914 
915 	/* Destination */
916 	struct dst_entry *dst;
917 	/* Source address. */
918 	union sctp_addr saddr;
919 
920 	/* When was the last time(in jiffies) that a data packet was sent on
921 	 * this transport?  This is used to adjust the cwnd when the transport
922 	 * becomes inactive.
923 	 */
924 	unsigned long last_time_used;
925 
926 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
927 	 * the destination address every heartbeat interval.
928 	 */
929 	unsigned long hbinterval;
930 
931 	/* SACK delay timeout */
932 	unsigned long sackdelay;
933 
934 	/* When was the last time (in jiffies) that we heard from this
935 	 * transport?  We use this to pick new active and retran paths.
936 	 */
937 	unsigned long last_time_heard;
938 
939 	/* Last time(in jiffies) when cwnd is reduced due to the congestion
940 	 * indication based on ECNE chunk.
941 	 */
942 	unsigned long last_time_ecne_reduced;
943 
944 	/* This is the max_retrans value for the transport and will
945 	 * be initialized from the assocs value.  This can be changed
946 	 * using SCTP_SET_PEER_ADDR_PARAMS socket option.
947 	 */
948 	__u16 pathmaxrxt;
949 
950 	/* is the Path MTU update pending on this tranport */
951 	__u8 pmtu_pending;
952 
953 	/* PMTU	      : The current known path MTU.  */
954 	__u32 pathmtu;
955 
956 	/* Flags controling Heartbeat, SACK delay, and Path MTU Discovery. */
957 	__u32 param_flags;
958 
959 	/* The number of times INIT has been sent on this transport. */
960 	int init_sent_count;
961 
962 	/* state       : The current state of this destination,
963 	 *             : i.e. SCTP_ACTIVE, SCTP_INACTIVE, SCTP_UNKOWN.
964 	 */
965 	int state;
966 
967 	/* These are the error stats for this destination.  */
968 
969 	/* Error count : The current error count for this destination.	*/
970 	unsigned short error_count;
971 
972 	/* Per	       : A timer used by each destination.
973 	 * Destination :
974 	 * Timer       :
975 	 *
976 	 * [Everywhere else in the text this is called T3-rtx. -ed]
977 	 */
978 	struct timer_list T3_rtx_timer;
979 
980 	/* Heartbeat timer is per destination. */
981 	struct timer_list hb_timer;
982 
983 	/* Since we're using per-destination retransmission timers
984 	 * (see above), we're also using per-destination "transmitted"
985 	 * queues.  This probably ought to be a private struct
986 	 * accessible only within the outqueue, but it's not, yet.
987 	 */
988 	struct list_head transmitted;
989 
990 	/* We build bundle-able packets for this transport here.  */
991 	struct sctp_packet packet;
992 
993 	/* This is the list of transports that have chunks to send.  */
994 	struct list_head send_ready;
995 
996 	int malloced; /* Is this structure kfree()able? */
997 
998 	/* State information saved for SFR_CACC algorithm. The key
999 	 * idea in SFR_CACC is to maintain state at the sender on a
1000 	 * per-destination basis when a changeover happens.
1001 	 *	char changeover_active;
1002 	 *	char cycling_changeover;
1003 	 *	__u32 next_tsn_at_change;
1004 	 *	char cacc_saw_newack;
1005 	 */
1006 	struct {
1007 		/* An unsigned integer, which stores the next TSN to be
1008 		 * used by the sender, at the moment of changeover.
1009 		 */
1010 		__u32 next_tsn_at_change;
1011 
1012 		/* A flag which indicates the occurrence of a changeover */
1013 		char changeover_active;
1014 
1015 		/* A flag which indicates whether the change of primary is
1016 		 * the first switch to this destination address during an
1017 		 * active switch.
1018 		 */
1019 		char cycling_changeover;
1020 
1021 		/* A temporary flag, which is used during the processing of
1022 		 * a SACK to estimate the causative TSN(s)'s group.
1023 		 */
1024 		char cacc_saw_newack;
1025 	} cacc;
1026 
1027 	/* 64-bit random number sent with heartbeat. */
1028 	__u64 hb_nonce;
1029 };
1030 
1031 struct sctp_transport *sctp_transport_new(const union sctp_addr *,
1032 					  gfp_t);
1033 void sctp_transport_set_owner(struct sctp_transport *,
1034 			      struct sctp_association *);
1035 void sctp_transport_route(struct sctp_transport *, union sctp_addr *,
1036 			  struct sctp_sock *);
1037 void sctp_transport_pmtu(struct sctp_transport *);
1038 void sctp_transport_free(struct sctp_transport *);
1039 void sctp_transport_reset_timers(struct sctp_transport *);
1040 void sctp_transport_hold(struct sctp_transport *);
1041 void sctp_transport_put(struct sctp_transport *);
1042 void sctp_transport_update_rto(struct sctp_transport *, __u32);
1043 void sctp_transport_raise_cwnd(struct sctp_transport *, __u32, __u32);
1044 void sctp_transport_lower_cwnd(struct sctp_transport *, sctp_lower_cwnd_t);
1045 unsigned long sctp_transport_timeout(struct sctp_transport *);
1046 void sctp_transport_reset(struct sctp_transport *);
1047 void sctp_transport_update_pmtu(struct sctp_transport *, u32);
1048 
1049 
1050 /* This is the structure we use to queue packets as they come into
1051  * SCTP.  We write packets to it and read chunks from it.
1052  */
1053 struct sctp_inq {
1054 	/* This is actually a queue of sctp_chunk each
1055 	 * containing a partially decoded packet.
1056 	 */
1057 	struct list_head in_chunk_list;
1058 	/* This is the packet which is currently off the in queue and is
1059 	 * being worked on through the inbound chunk processing.
1060 	 */
1061 	struct sctp_chunk *in_progress;
1062 
1063 	/* This is the delayed task to finish delivering inbound
1064 	 * messages.
1065 	 */
1066 	struct work_struct immediate;
1067 
1068 	int malloced;	     /* Is this structure kfree()able?	*/
1069 };
1070 
1071 void sctp_inq_init(struct sctp_inq *);
1072 void sctp_inq_free(struct sctp_inq *);
1073 void sctp_inq_push(struct sctp_inq *, struct sctp_chunk *packet);
1074 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *);
1075 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *);
1076 void sctp_inq_set_th_handler(struct sctp_inq *, work_func_t);
1077 
1078 /* This is the structure we use to hold outbound chunks.  You push
1079  * chunks in and they automatically pop out the other end as bundled
1080  * packets (it calls (*output_handler)()).
1081  *
1082  * This structure covers sections 6.3, 6.4, 6.7, 6.8, 6.10, 7., 8.1,
1083  * and 8.2 of the v13 draft.
1084  *
1085  * It handles retransmissions.	The connection to the timeout portion
1086  * of the state machine is through sctp_..._timeout() and timeout_handler.
1087  *
1088  * If you feed it SACKs, it will eat them.
1089  *
1090  * If you give it big chunks, it will fragment them.
1091  *
1092  * It assigns TSN's to data chunks.  This happens at the last possible
1093  * instant before transmission.
1094  *
1095  * When free()'d, it empties itself out via output_handler().
1096  */
1097 struct sctp_outq {
1098 	struct sctp_association *asoc;
1099 
1100 	/* Data pending that has never been transmitted.  */
1101 	struct list_head out_chunk_list;
1102 
1103 	unsigned out_qlen;	/* Total length of queued data chunks. */
1104 
1105 	/* Error of send failed, may used in SCTP_SEND_FAILED event. */
1106 	unsigned error;
1107 
1108 	/* These are control chunks we want to send.  */
1109 	struct list_head control_chunk_list;
1110 
1111 	/* These are chunks that have been sacked but are above the
1112 	 * CTSN, or cumulative tsn ack point.
1113 	 */
1114 	struct list_head sacked;
1115 
1116 	/* Put chunks on this list to schedule them for
1117 	 * retransmission.
1118 	 */
1119 	struct list_head retransmit;
1120 
1121 	/* Put chunks on this list to save them for FWD TSN processing as
1122 	 * they were abandoned.
1123 	 */
1124 	struct list_head abandoned;
1125 
1126 	/* How many unackd bytes do we have in-flight?	*/
1127 	__u32 outstanding_bytes;
1128 
1129 	/* Corked? */
1130 	char cork;
1131 
1132 	/* Is this structure empty?  */
1133 	char empty;
1134 
1135 	/* Are we kfree()able? */
1136 	char malloced;
1137 };
1138 
1139 void sctp_outq_init(struct sctp_association *, struct sctp_outq *);
1140 void sctp_outq_teardown(struct sctp_outq *);
1141 void sctp_outq_free(struct sctp_outq*);
1142 int sctp_outq_tail(struct sctp_outq *, struct sctp_chunk *chunk);
1143 int sctp_outq_flush(struct sctp_outq *, int);
1144 int sctp_outq_sack(struct sctp_outq *, struct sctp_sackhdr *);
1145 int sctp_outq_is_empty(const struct sctp_outq *);
1146 void sctp_outq_restart(struct sctp_outq *);
1147 
1148 void sctp_retransmit(struct sctp_outq *, struct sctp_transport *,
1149 		     sctp_retransmit_reason_t);
1150 void sctp_retransmit_mark(struct sctp_outq *, struct sctp_transport *, __u8);
1151 int sctp_outq_uncork(struct sctp_outq *);
1152 /* Uncork and flush an outqueue.  */
1153 static inline void sctp_outq_cork(struct sctp_outq *q)
1154 {
1155 	q->cork = 1;
1156 }
1157 
1158 /* These bind address data fields common between endpoints and associations */
1159 struct sctp_bind_addr {
1160 
1161 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1162 	 *
1163 	 * SCTP Port:	The local SCTP port number the endpoint is
1164 	 *		bound to.
1165 	 */
1166 	__u16 port;
1167 
1168 	/* RFC 2960 12.1 Parameters necessary for the SCTP instance
1169 	 *
1170 	 * Address List: The list of IP addresses that this instance
1171 	 *	has bound.  This information is passed to one's
1172 	 *	peer(s) in INIT and INIT ACK chunks.
1173 	 */
1174 	struct list_head address_list;
1175 
1176 	int malloced;	     /* Are we kfree()able?  */
1177 };
1178 
1179 void sctp_bind_addr_init(struct sctp_bind_addr *, __u16 port);
1180 void sctp_bind_addr_free(struct sctp_bind_addr *);
1181 int sctp_bind_addr_copy(struct sctp_bind_addr *dest,
1182 			const struct sctp_bind_addr *src,
1183 			sctp_scope_t scope, gfp_t gfp,
1184 			int flags);
1185 int sctp_add_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1186 		       __u8 use_as_src, gfp_t gfp);
1187 int sctp_del_bind_addr(struct sctp_bind_addr *, union sctp_addr *,
1188 			void fastcall (*rcu_call)(struct rcu_head *,
1189 					  void (*func)(struct rcu_head *)));
1190 int sctp_bind_addr_match(struct sctp_bind_addr *, const union sctp_addr *,
1191 			 struct sctp_sock *);
1192 union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
1193 					const union sctp_addr	*addrs,
1194 					int			addrcnt,
1195 					struct sctp_sock	*opt);
1196 union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
1197 					 int *addrs_len,
1198 					 gfp_t gfp);
1199 int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw, int len,
1200 			   __u16 port, gfp_t gfp);
1201 
1202 sctp_scope_t sctp_scope(const union sctp_addr *);
1203 int sctp_in_scope(const union sctp_addr *addr, const sctp_scope_t scope);
1204 int sctp_is_any(const union sctp_addr *addr);
1205 int sctp_addr_is_valid(const union sctp_addr *addr);
1206 
1207 
1208 /* What type of endpoint?  */
1209 typedef enum {
1210 	SCTP_EP_TYPE_SOCKET,
1211 	SCTP_EP_TYPE_ASSOCIATION,
1212 } sctp_endpoint_type_t;
1213 
1214 /*
1215  * A common base class to bridge the implmentation view of a
1216  * socket (usually listening) endpoint versus an association's
1217  * local endpoint.
1218  * This common structure is useful for several purposes:
1219  *   1) Common interface for lookup routines.
1220  *	a) Subfunctions work for either endpoint or association
1221  *	b) Single interface to lookup allows hiding the lookup lock rather
1222  *	   than acquiring it externally.
1223  *   2) Common interface for the inbound chunk handling/state machine.
1224  *   3) Common object handling routines for reference counting, etc.
1225  *   4) Disentangle association lookup from endpoint lookup, where we
1226  *	do not have to find our endpoint to find our association.
1227  *
1228  */
1229 
1230 struct sctp_ep_common {
1231 	/* Fields to help us manage our entries in the hash tables. */
1232 	struct sctp_ep_common *next;
1233 	struct sctp_ep_common **pprev;
1234 	int hashent;
1235 
1236 	/* Runtime type information.  What kind of endpoint is this? */
1237 	sctp_endpoint_type_t type;
1238 
1239 	/* Some fields to help us manage this object.
1240 	 *   refcnt   - Reference count access to this object.
1241 	 *   dead     - Do not attempt to use this object.
1242 	 *   malloced - Do we need to kfree this object?
1243 	 */
1244 	atomic_t    refcnt;
1245 	char	    dead;
1246 	char	    malloced;
1247 
1248 	/* What socket does this endpoint belong to?  */
1249 	struct sock *sk;
1250 
1251 	/* This is where we receive inbound chunks.  */
1252 	struct sctp_inq	  inqueue;
1253 
1254 	/* This substructure includes the defining parameters of the
1255 	 * endpoint:
1256 	 * bind_addr.port is our shared port number.
1257 	 * bind_addr.address_list is our set of local IP addresses.
1258 	 */
1259 	struct sctp_bind_addr bind_addr;
1260 };
1261 
1262 
1263 /* RFC Section 1.4 Key Terms
1264  *
1265  * o SCTP endpoint: The logical sender/receiver of SCTP packets. On a
1266  *   multi-homed host, an SCTP endpoint is represented to its peers as a
1267  *   combination of a set of eligible destination transport addresses to
1268  *   which SCTP packets can be sent and a set of eligible source
1269  *   transport addresses from which SCTP packets can be received.
1270  *   All transport addresses used by an SCTP endpoint must use the
1271  *   same port number, but can use multiple IP addresses. A transport
1272  *   address used by an SCTP endpoint must not be used by another
1273  *   SCTP endpoint. In other words, a transport address is unique
1274  *   to an SCTP endpoint.
1275  *
1276  * From an implementation perspective, each socket has one of these.
1277  * A TCP-style socket will have exactly one association on one of
1278  * these.  An UDP-style socket will have multiple associations hanging
1279  * off one of these.
1280  */
1281 
1282 struct sctp_endpoint {
1283 	/* Common substructure for endpoint and association. */
1284 	struct sctp_ep_common base;
1285 
1286 	/* Associations: A list of current associations and mappings
1287 	 *	      to the data consumers for each association. This
1288 	 *	      may be in the form of a hash table or other
1289 	 *	      implementation dependent structure. The data
1290 	 *	      consumers may be process identification
1291 	 *	      information such as file descriptors, named pipe
1292 	 *	      pointer, or table pointers dependent on how SCTP
1293 	 *	      is implemented.
1294 	 */
1295 	/* This is really a list of struct sctp_association entries. */
1296 	struct list_head asocs;
1297 
1298 	/* Secret Key: A secret key used by this endpoint to compute
1299 	 *	      the MAC.	This SHOULD be a cryptographic quality
1300 	 *	      random number with a sufficient length.
1301 	 *	      Discussion in [RFC1750] can be helpful in
1302 	 *	      selection of the key.
1303 	 */
1304 	__u8 secret_key[SCTP_HOW_MANY_SECRETS][SCTP_SECRET_SIZE];
1305 	int current_key;
1306 	int last_key;
1307 	int key_changed_at;
1308 
1309  	/* digest:  This is a digest of the sctp cookie.  This field is
1310  	 * 	    only used on the receive path when we try to validate
1311  	 * 	    that the cookie has not been tampered with.  We put
1312  	 * 	    this here so we pre-allocate this once and can re-use
1313  	 * 	    on every receive.
1314  	 */
1315  	__u8 *digest;
1316 
1317 	/* sendbuf acct. policy.	*/
1318 	__u32 sndbuf_policy;
1319 
1320 	/* rcvbuf acct. policy.	*/
1321 	__u32 rcvbuf_policy;
1322 
1323 	/* SCTP AUTH: array of the HMACs that will be allocated
1324 	 * we need this per association so that we don't serialize
1325 	 */
1326 	struct crypto_hash **auth_hmacs;
1327 
1328 	/* SCTP-AUTH: hmacs for the endpoint encoded into parameter */
1329 	 struct sctp_hmac_algo_param *auth_hmacs_list;
1330 
1331 	/* SCTP-AUTH: chunks to authenticate encoded into parameter */
1332 	struct sctp_chunks_param *auth_chunk_list;
1333 
1334 	/* SCTP-AUTH: endpoint shared keys */
1335 	struct list_head endpoint_shared_keys;
1336 	__u16 active_key_id;
1337 };
1338 
1339 /* Recover the outter endpoint structure. */
1340 static inline struct sctp_endpoint *sctp_ep(struct sctp_ep_common *base)
1341 {
1342 	struct sctp_endpoint *ep;
1343 
1344 	ep = container_of(base, struct sctp_endpoint, base);
1345 	return ep;
1346 }
1347 
1348 /* These are function signatures for manipulating endpoints.  */
1349 struct sctp_endpoint *sctp_endpoint_new(struct sock *, gfp_t);
1350 void sctp_endpoint_free(struct sctp_endpoint *);
1351 void sctp_endpoint_put(struct sctp_endpoint *);
1352 void sctp_endpoint_hold(struct sctp_endpoint *);
1353 void sctp_endpoint_add_asoc(struct sctp_endpoint *, struct sctp_association *);
1354 struct sctp_association *sctp_endpoint_lookup_assoc(
1355 	const struct sctp_endpoint *ep,
1356 	const union sctp_addr *paddr,
1357 	struct sctp_transport **);
1358 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *,
1359 				const union sctp_addr *);
1360 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *,
1361 					const union sctp_addr *);
1362 int sctp_has_association(const union sctp_addr *laddr,
1363 			 const union sctp_addr *paddr);
1364 
1365 int sctp_verify_init(const struct sctp_association *asoc, sctp_cid_t,
1366 		     sctp_init_chunk_t *peer_init, struct sctp_chunk *chunk,
1367 		     struct sctp_chunk **err_chunk);
1368 int sctp_process_init(struct sctp_association *, sctp_cid_t cid,
1369 		      const union sctp_addr *peer,
1370 		      sctp_init_chunk_t *init, gfp_t gfp);
1371 __u32 sctp_generate_tag(const struct sctp_endpoint *);
1372 __u32 sctp_generate_tsn(const struct sctp_endpoint *);
1373 
1374 struct sctp_inithdr_host {
1375 	__u32 init_tag;
1376 	__u32 a_rwnd;
1377 	__u16 num_outbound_streams;
1378 	__u16 num_inbound_streams;
1379 	__u32 initial_tsn;
1380 };
1381 
1382 /* RFC2960
1383  *
1384  * 12. Recommended Transmission Control Block (TCB) Parameters
1385  *
1386  * This section details a recommended set of parameters that should
1387  * be contained within the TCB for an implementation. This section is
1388  * for illustrative purposes and should not be deemed as requirements
1389  * on an implementation or as an exhaustive list of all parameters
1390  * inside an SCTP TCB. Each implementation may need its own additional
1391  * parameters for optimization.
1392  */
1393 
1394 
1395 /* Here we have information about each individual association. */
1396 struct sctp_association {
1397 
1398 	/* A base structure common to endpoint and association.
1399 	 * In this context, it represents the associations's view
1400 	 * of the local endpoint of the association.
1401 	 */
1402 	struct sctp_ep_common base;
1403 
1404 	/* Associations on the same socket. */
1405 	struct list_head asocs;
1406 
1407 	/* association id. */
1408 	sctp_assoc_t assoc_id;
1409 
1410 	/* This is our parent endpoint.	 */
1411 	struct sctp_endpoint *ep;
1412 
1413 	/* These are those association elements needed in the cookie.  */
1414 	struct sctp_cookie c;
1415 
1416 	/* This is all information about our peer.  */
1417 	struct {
1418 		/* rwnd
1419 		 *
1420 		 * Peer Rwnd   : Current calculated value of the peer's rwnd.
1421 		 */
1422 		__u32 rwnd;
1423 
1424 		/* transport_addr_list
1425 		 *
1426 		 * Peer	       : A list of SCTP transport addresses that the
1427 		 * Transport   : peer is bound to. This information is derived
1428 		 * Address     : from the INIT or INIT ACK and is used to
1429 		 * List	       : associate an inbound packet with a given
1430 		 *	       : association. Normally this information is
1431 		 *	       : hashed or keyed for quick lookup and access
1432 		 *	       : of the TCB.
1433 		 *	       : The list is also initialized with the list
1434 		 *	       : of addresses passed with the sctp_connectx()
1435 		 *	       : call.
1436 		 *
1437 		 * It is a list of SCTP_transport's.
1438 		 */
1439 		struct list_head transport_addr_list;
1440 
1441 		/* transport_count
1442 		 *
1443 		 * Peer        : A count of the number of peer addresses
1444 		 * Transport   : in the Peer Transport Address List.
1445 		 * Address     :
1446 		 * Count       :
1447 		 */
1448 		__u16 transport_count;
1449 
1450 		/* port
1451 		 *   The transport layer port number.
1452 		 */
1453 		__u16 port;
1454 
1455 		/* primary_path
1456 		 *
1457 		 * Primary     : This is the current primary destination
1458 		 * Path	       : transport address of the peer endpoint.  It
1459 		 *	       : may also specify a source transport address
1460 		 *	       : on this endpoint.
1461 		 *
1462 		 * All of these paths live on transport_addr_list.
1463 		 *
1464 		 * At the bakeoffs, we discovered that the intent of
1465 		 * primaryPath is that it only changes when the ULP
1466 		 * asks to have it changed.  We add the activePath to
1467 		 * designate the connection we are currently using to
1468 		 * transmit new data and most control chunks.
1469 		 */
1470 		struct sctp_transport *primary_path;
1471 
1472 		/* Cache the primary path address here, when we
1473 		 * need a an address for msg_name.
1474 		 */
1475 		union sctp_addr primary_addr;
1476 
1477 		/* active_path
1478 		 *   The path that we are currently using to
1479 		 *   transmit new data and most control chunks.
1480 		 */
1481 		struct sctp_transport *active_path;
1482 
1483 		/* retran_path
1484 		 *
1485 		 * RFC2960 6.4 Multi-homed SCTP Endpoints
1486 		 * ...
1487 		 * Furthermore, when its peer is multi-homed, an
1488 		 * endpoint SHOULD try to retransmit a chunk to an
1489 		 * active destination transport address that is
1490 		 * different from the last destination address to
1491 		 * which the DATA chunk was sent.
1492 		 */
1493 		struct sctp_transport *retran_path;
1494 
1495 		/* Pointer to last transport I have sent on.  */
1496 		struct sctp_transport *last_sent_to;
1497 
1498 		/* This is the last transport I have received DATA on.	*/
1499 		struct sctp_transport *last_data_from;
1500 
1501 		/*
1502 		 * Mapping  An array of bits or bytes indicating which out of
1503 		 * Array    order TSN's have been received (relative to the
1504 		 *	    Last Rcvd TSN). If no gaps exist, i.e. no out of
1505 		 *	    order packets have been received, this array
1506 		 *	    will be set to all zero. This structure may be
1507 		 *	    in the form of a circular buffer or bit array.
1508 		 *
1509 		 * Last Rcvd   : This is the last TSN received in
1510 		 * TSN	       : sequence. This value is set initially by
1511 		 *	       : taking the peer's Initial TSN, received in
1512 		 *	       : the INIT or INIT ACK chunk, and subtracting
1513 		 *	       : one from it.
1514 		 *
1515 		 * Throughout most of the specification this is called the
1516 		 * "Cumulative TSN ACK Point".	In this case, we
1517 		 * ignore the advice in 12.2 in favour of the term
1518 		 * used in the bulk of the text.  This value is hidden
1519 		 * in tsn_map--we get it by calling sctp_tsnmap_get_ctsn().
1520 		 */
1521 		struct sctp_tsnmap tsn_map;
1522 		__u8 _map[sctp_tsnmap_storage_size(SCTP_TSN_MAP_SIZE)];
1523 
1524 		/* Ack State   : This flag indicates if the next received
1525 		 *             : packet is to be responded to with a
1526 		 *             : SACK. This is initializedto 0.  When a packet
1527 		 *             : is received it is incremented. If this value
1528 		 *             : reaches 2 or more, a SACK is sent and the
1529 		 *             : value is reset to 0. Note: This is used only
1530 		 *             : when no DATA chunks are received out of
1531 		 *             : order.  When DATA chunks are out of order,
1532 		 *             : SACK's are not delayed (see Section 6).
1533 		 */
1534 		__u8    sack_needed;     /* Do we need to sack the peer? */
1535 
1536 		/* These are capabilities which our peer advertised.  */
1537 		__u8	ecn_capable;	 /* Can peer do ECN? */
1538 		__u8	ipv4_address;	 /* Peer understands IPv4 addresses? */
1539 		__u8	ipv6_address;	 /* Peer understands IPv6 addresses? */
1540 		__u8	hostname_address;/* Peer understands DNS addresses? */
1541 		__u8    asconf_capable;  /* Does peer support ADDIP? */
1542 		__u8    prsctp_capable;  /* Can peer do PR-SCTP? */
1543 		__u8	auth_capable;	 /* Is peer doing SCTP-AUTH? */
1544 		__u8	addip_capable;	 /* Can peer do ADD-IP */
1545 
1546 		__u32   adaptation_ind;	 /* Adaptation Code point. */
1547 
1548 		/* This mask is used to disable sending the ASCONF chunk
1549 		 * with specified parameter to peer.
1550 		 */
1551 		__be16 addip_disabled_mask;
1552 
1553 		struct sctp_inithdr_host i;
1554 		int cookie_len;
1555 		void *cookie;
1556 
1557 		/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1558 		 * C1) ... "Peer-Serial-Number'. This value MUST be initialized to the
1559 		 * Initial TSN Value minus 1
1560 		 */
1561 		__u32 addip_serial;
1562 
1563 		/* SCTP-AUTH: We need to know pears random number, hmac list
1564 		 * and authenticated chunk list.  All that is part of the
1565 		 * cookie and these are just pointers to those locations
1566 		 */
1567 		sctp_random_param_t *peer_random;
1568 		sctp_chunks_param_t *peer_chunks;
1569 		sctp_hmac_algo_param_t *peer_hmacs;
1570 	} peer;
1571 
1572 	/* State       : A state variable indicating what state the
1573 	 *	       : association is in, i.e. COOKIE-WAIT,
1574 	 *	       : COOKIE-ECHOED, ESTABLISHED, SHUTDOWN-PENDING,
1575 	 *	       : SHUTDOWN-SENT, SHUTDOWN-RECEIVED, SHUTDOWN-ACK-SENT.
1576 	 *
1577 	 *		Note: No "CLOSED" state is illustrated since if a
1578 	 *		association is "CLOSED" its TCB SHOULD be removed.
1579 	 *
1580 	 *		In this implementation we DO have a CLOSED
1581 	 *		state which is used during initiation and shutdown.
1582 	 *
1583 	 *		State takes values from SCTP_STATE_*.
1584 	 */
1585 	sctp_state_t state;
1586 
1587 	/* The cookie life I award for any cookie.  */
1588 	struct timeval cookie_life;
1589 
1590 	/* Overall     : The overall association error count.
1591 	 * Error Count : [Clear this any time I get something.]
1592 	 */
1593 	int overall_error_count;
1594 
1595 	/* These are the association's initial, max, and min RTO values.
1596 	 * These values will be initialized by system defaults, but can
1597 	 * be modified via the SCTP_RTOINFO socket option.
1598 	 */
1599 	unsigned long rto_initial;
1600 	unsigned long rto_max;
1601 	unsigned long rto_min;
1602 
1603 	/* Maximum number of new data packets that can be sent in a burst.  */
1604 	int max_burst;
1605 
1606 	/* This is the max_retrans value for the association.  This value will
1607 	 * be initialized initialized from system defaults, but can be
1608 	 * modified by the SCTP_ASSOCINFO socket option.
1609 	 */
1610 	int max_retrans;
1611 
1612 	/* Maximum number of times the endpoint will retransmit INIT  */
1613 	__u16 max_init_attempts;
1614 
1615 	/* How many times have we resent an INIT? */
1616 	__u16 init_retries;
1617 
1618 	/* The largest timeout or RTO value to use in attempting an INIT */
1619 	unsigned long max_init_timeo;
1620 
1621 	/* Heartbeat interval: The endpoint sends out a Heartbeat chunk to
1622 	 * the destination address every heartbeat interval. This value
1623 	 * will be inherited by all new transports.
1624 	 */
1625 	unsigned long hbinterval;
1626 
1627 	/* This is the max_retrans value for new transports in the
1628 	 * association.
1629 	 */
1630 	__u16 pathmaxrxt;
1631 
1632 	/* Flag that path mtu update is pending */
1633 	__u8   pmtu_pending;
1634 
1635 	/* Association : The smallest PMTU discovered for all of the
1636 	 * PMTU	       : peer's transport addresses.
1637 	 */
1638 	__u32 pathmtu;
1639 
1640 	/* Flags controling Heartbeat, SACK delay, and Path MTU Discovery. */
1641 	__u32 param_flags;
1642 
1643 	/* SACK delay timeout */
1644 	unsigned long sackdelay;
1645 
1646 
1647 	unsigned long timeouts[SCTP_NUM_TIMEOUT_TYPES];
1648 	struct timer_list timers[SCTP_NUM_TIMEOUT_TYPES];
1649 
1650 	/* Transport to which SHUTDOWN chunk was last sent.  */
1651 	struct sctp_transport *shutdown_last_sent_to;
1652 
1653 	/* Transport to which INIT chunk was last sent.  */
1654 	struct sctp_transport *init_last_sent_to;
1655 
1656 	/* Next TSN    : The next TSN number to be assigned to a new
1657 	 *	       : DATA chunk.  This is sent in the INIT or INIT
1658 	 *	       : ACK chunk to the peer and incremented each
1659 	 *	       : time a DATA chunk is assigned a TSN
1660 	 *	       : (normally just prior to transmit or during
1661 	 *	       : fragmentation).
1662 	 */
1663 	__u32 next_tsn;
1664 
1665 	/*
1666 	 * Last Rcvd   : This is the last TSN received in sequence.  This value
1667 	 * TSN	       : is set initially by taking the peer's Initial TSN,
1668 	 *	       : received in the INIT or INIT ACK chunk, and
1669 	 *	       : subtracting one from it.
1670 	 *
1671 	 * Most of RFC 2960 refers to this as the Cumulative TSN Ack Point.
1672 	 */
1673 
1674 	__u32 ctsn_ack_point;
1675 
1676 	/* PR-SCTP Advanced.Peer.Ack.Point */
1677 	__u32 adv_peer_ack_point;
1678 
1679 	/* Highest TSN that is acknowledged by incoming SACKs. */
1680 	__u32 highest_sacked;
1681 
1682 	/* The number of unacknowledged data chunks.  Reported through
1683 	 * the SCTP_STATUS sockopt.
1684 	 */
1685 	__u16 unack_data;
1686 
1687 	/* This is the association's receive buffer space.  This value is used
1688 	 * to set a_rwnd field in an INIT or a SACK chunk.
1689 	 */
1690 	__u32 rwnd;
1691 
1692 	/* This is the last advertised value of rwnd over a SACK chunk. */
1693 	__u32 a_rwnd;
1694 
1695 	/* Number of bytes by which the rwnd has slopped.  The rwnd is allowed
1696 	 * to slop over a maximum of the association's frag_point.
1697 	 */
1698 	__u32 rwnd_over;
1699 
1700 	/* This is the sndbuf size in use for the association.
1701 	 * This corresponds to the sndbuf size for the association,
1702 	 * as specified in the sk->sndbuf.
1703 	 */
1704 	int sndbuf_used;
1705 
1706 	/* This is the amount of memory that this association has allocated
1707 	 * in the receive path at any given time.
1708 	 */
1709 	atomic_t rmem_alloc;
1710 
1711 	/* This is the wait queue head for send requests waiting on
1712 	 * the association sndbuf space.
1713 	 */
1714 	wait_queue_head_t	wait;
1715 
1716 	/* The message size at which SCTP fragmentation will occur. */
1717 	__u32 frag_point;
1718 
1719 	/* Counter used to count INIT errors. */
1720 	int init_err_counter;
1721 
1722 	/* Count the number of INIT cycles (for doubling timeout). */
1723 	int init_cycle;
1724 
1725 	/* Default send parameters. */
1726 	__u16 default_stream;
1727 	__u16 default_flags;
1728 	__u32 default_ppid;
1729 	__u32 default_context;
1730 	__u32 default_timetolive;
1731 
1732 	/* Default receive parameters */
1733 	__u32 default_rcv_context;
1734 
1735 	/* This tracks outbound ssn for a given stream.	 */
1736 	struct sctp_ssnmap *ssnmap;
1737 
1738 	/* All outbound chunks go through this structure.  */
1739 	struct sctp_outq outqueue;
1740 
1741 	/* A smart pipe that will handle reordering and fragmentation,
1742 	 * as well as handle passing events up to the ULP.
1743 	 */
1744 	struct sctp_ulpq ulpq;
1745 
1746 	/* Last TSN that caused an ECNE Chunk to be sent.  */
1747 	__u32 last_ecne_tsn;
1748 
1749 	/* Last TSN that caused a CWR Chunk to be sent.	 */
1750 	__u32 last_cwr_tsn;
1751 
1752 	/* How many duplicated TSNs have we seen?  */
1753 	int numduptsns;
1754 
1755 	/* Number of seconds of idle time before an association is closed.
1756 	 * In the association context, this is really used as a boolean
1757 	 * since the real timeout is stored in the timeouts array
1758 	 */
1759 	__u32 autoclose;
1760 
1761 	/* These are to support
1762 	 * "SCTP Extensions for Dynamic Reconfiguration of IP Addresses
1763 	 *  and Enforcement of Flow and Message Limits"
1764 	 * <draft-ietf-tsvwg-addip-sctp-02.txt>
1765 	 * or "ADDIP" for short.
1766 	 */
1767 
1768 
1769 
1770 	/* ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1771 	 *
1772 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1773 	 * unacknowledged at any one time.  If a sender, after sending
1774 	 * an ASCONF chunk, decides it needs to transfer another
1775 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1776 	 * returns from the previous ASCONF Chunk before sending a
1777 	 * subsequent ASCONF. Note this restriction binds each side,
1778 	 * so at any time two ASCONF may be in-transit on any given
1779 	 * association (one sent from each endpoint).
1780 	 *
1781 	 * [This is our one-and-only-one ASCONF in flight.  If we do
1782 	 * not have an ASCONF in flight, this is NULL.]
1783 	 */
1784 	struct sctp_chunk *addip_last_asconf;
1785 
1786 	/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.
1787 	 *
1788 	 * IMPLEMENTATION NOTE: As an optimization a receiver may wish
1789 	 * to save the last ASCONF-ACK for some predetermined period
1790 	 * of time and instead of re-processing the ASCONF (with the
1791 	 * same serial number) it may just re-transmit the
1792 	 * ASCONF-ACK. It may wish to use the arrival of a new serial
1793 	 * number to discard the previously saved ASCONF-ACK or any
1794 	 * other means it may choose to expire the saved ASCONF-ACK.
1795 	 *
1796 	 * [This is our saved ASCONF-ACK.  We invalidate it when a new
1797 	 * ASCONF serial number arrives.]
1798 	 */
1799 	struct sctp_chunk *addip_last_asconf_ack;
1800 
1801 	/* These ASCONF chunks are waiting to be sent.
1802 	 *
1803 	 * These chunaks can't be pushed to outqueue until receiving
1804 	 * ASCONF_ACK for the previous ASCONF indicated by
1805 	 * addip_last_asconf, so as to guarantee that only one ASCONF
1806 	 * is in flight at any time.
1807 	 *
1808 	 * ADDIP Section 4.1.1 Congestion Control of ASCONF Chunks
1809 	 *
1810 	 * In defining the ASCONF Chunk transfer procedures, it is
1811 	 * essential that these transfers MUST NOT cause congestion
1812 	 * within the network.	To achieve this, we place these
1813 	 * restrictions on the transfer of ASCONF Chunks:
1814 	 *
1815 	 * R1) One and only one ASCONF Chunk MAY be in transit and
1816 	 * unacknowledged at any one time.  If a sender, after sending
1817 	 * an ASCONF chunk, decides it needs to transfer another
1818 	 * ASCONF Chunk, it MUST wait until the ASCONF-ACK Chunk
1819 	 * returns from the previous ASCONF Chunk before sending a
1820 	 * subsequent ASCONF. Note this restriction binds each side,
1821 	 * so at any time two ASCONF may be in-transit on any given
1822 	 * association (one sent from each endpoint).
1823 	 *
1824 	 *
1825 	 * [I really think this is EXACTLY the sort of intelligence
1826 	 *  which already resides in sctp_outq.	 Please move this
1827 	 *  queue and its supporting logic down there.	--piggy]
1828 	 */
1829 	struct list_head addip_chunk_list;
1830 
1831 	/* ADDIP Section 4.1 ASCONF Chunk Procedures
1832 	 *
1833 	 * A2) A serial number should be assigned to the Chunk. The
1834 	 * serial number SHOULD be a monotonically increasing
1835 	 * number. The serial number SHOULD be initialized at
1836 	 * the start of the association to the same value as the
1837 	 * Initial TSN and every time a new ASCONF chunk is created
1838 	 * it is incremented by one after assigning the serial number
1839 	 * to the newly created chunk.
1840 	 *
1841 	 * ADDIP
1842 	 * 3.1.1  Address/Stream Configuration Change Chunk (ASCONF)
1843 	 *
1844 	 * Serial Number : 32 bits (unsigned integer)
1845 	 *
1846 	 * This value represents a Serial Number for the ASCONF
1847 	 * Chunk. The valid range of Serial Number is from 0 to
1848 	 * 4294967295 (2^32 - 1).  Serial Numbers wrap back to 0
1849 	 * after reaching 4294967295.
1850 	 */
1851 	__u32 addip_serial;
1852 
1853 	/* SCTP AUTH: list of the endpoint shared keys.  These
1854 	 * keys are provided out of band by the user applicaton
1855 	 * and can't change during the lifetime of the association
1856 	 */
1857 	struct list_head endpoint_shared_keys;
1858 
1859 	/* SCTP AUTH:
1860 	 * The current generated assocaition shared key (secret)
1861 	 */
1862 	struct sctp_auth_bytes *asoc_shared_key;
1863 
1864 	/* SCTP AUTH: hmac id of the first peer requested algorithm
1865 	 * that we support.
1866 	 */
1867 	__u16 default_hmac_id;
1868 
1869 	__u16 active_key_id;
1870 
1871 	/* Need to send an ECNE Chunk? */
1872 	char need_ecne;
1873 
1874 	/* Is it a temporary association? */
1875 	char temp;
1876 };
1877 
1878 
1879 /* An eyecatcher for determining if we are really looking at an
1880  * association data structure.
1881  */
1882 enum {
1883 	SCTP_ASSOC_EYECATCHER = 0xa550c123,
1884 };
1885 
1886 /* Recover the outter association structure. */
1887 static inline struct sctp_association *sctp_assoc(struct sctp_ep_common *base)
1888 {
1889 	struct sctp_association *asoc;
1890 
1891 	asoc = container_of(base, struct sctp_association, base);
1892 	return asoc;
1893 }
1894 
1895 /* These are function signatures for manipulating associations.	 */
1896 
1897 
1898 struct sctp_association *
1899 sctp_association_new(const struct sctp_endpoint *, const struct sock *,
1900 		     sctp_scope_t scope, gfp_t gfp);
1901 void sctp_association_free(struct sctp_association *);
1902 void sctp_association_put(struct sctp_association *);
1903 void sctp_association_hold(struct sctp_association *);
1904 
1905 struct sctp_transport *sctp_assoc_choose_init_transport(
1906 	struct sctp_association *);
1907 struct sctp_transport *sctp_assoc_choose_shutdown_transport(
1908 	struct sctp_association *);
1909 void sctp_assoc_update_retran_path(struct sctp_association *);
1910 struct sctp_transport *sctp_assoc_lookup_paddr(const struct sctp_association *,
1911 					  const union sctp_addr *);
1912 int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
1913 			    const union sctp_addr *laddr);
1914 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *,
1915 				     const union sctp_addr *address,
1916 				     const gfp_t gfp,
1917 				     const int peer_state);
1918 void sctp_assoc_del_peer(struct sctp_association *asoc,
1919 			 const union sctp_addr *addr);
1920 void sctp_assoc_rm_peer(struct sctp_association *asoc,
1921 			 struct sctp_transport *peer);
1922 void sctp_assoc_control_transport(struct sctp_association *,
1923 				  struct sctp_transport *,
1924 				  sctp_transport_cmd_t, sctp_sn_error_t);
1925 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *, __u32);
1926 struct sctp_transport *sctp_assoc_is_match(struct sctp_association *,
1927 					   const union sctp_addr *,
1928 					   const union sctp_addr *);
1929 void sctp_assoc_migrate(struct sctp_association *, struct sock *);
1930 void sctp_assoc_update(struct sctp_association *old,
1931 		       struct sctp_association *new);
1932 
1933 __u32 sctp_association_get_next_tsn(struct sctp_association *);
1934 
1935 void sctp_assoc_sync_pmtu(struct sctp_association *);
1936 void sctp_assoc_rwnd_increase(struct sctp_association *, unsigned);
1937 void sctp_assoc_rwnd_decrease(struct sctp_association *, unsigned);
1938 void sctp_assoc_set_primary(struct sctp_association *,
1939 			    struct sctp_transport *);
1940 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *,
1941 				     gfp_t);
1942 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *,
1943 					 struct sctp_cookie*,
1944 					 gfp_t gfp);
1945 int sctp_assoc_set_id(struct sctp_association *, gfp_t);
1946 
1947 int sctp_cmp_addr_exact(const union sctp_addr *ss1,
1948 			const union sctp_addr *ss2);
1949 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc);
1950 
1951 /* A convenience structure to parse out SCTP specific CMSGs. */
1952 typedef struct sctp_cmsgs {
1953 	struct sctp_initmsg *init;
1954 	struct sctp_sndrcvinfo *info;
1955 } sctp_cmsgs_t;
1956 
1957 /* Structure for tracking memory objects */
1958 typedef struct {
1959 	char *label;
1960 	atomic_t *counter;
1961 } sctp_dbg_objcnt_entry_t;
1962 
1963 #endif /* __sctp_structs_h__ */
1964